The invention relates to a device for ensuring correct tooth engagement during coupling of two gearwheels, more specifically, an adjustable first gearwheel to a second gearwheel of a printing-material-processing machine, the engagement-ensuring device comprising a first adjustment device for adjusting the first gearwheel in a direction towards the second gearwheel during coupling, and also comprising a protrusion and a guide for guiding the protrusion during coupling.
Such devices are necessary in order for decoupled gearwheels to be brought together into a precise position during coupling to form a gear train.
In a device corresponding to the general type mentioned in the introduction hereto and described in the published German Patent Application DE 42 26 392 C1, a spring bolt is arranged on a first gearwheel that is accommodated in a pivotable frame member, and a segment ring with a centering groove is arranged on a second gearwheel accommodated in a stationary frame member. Although the spring bolt is pivotable about an articulating joint connecting the pivotable frame member to the stationary frame member, it cannot be pivoted about the central axis of the first gearwheel because the spring bolt is fastened to the pivotable frame member by a link. Before coupling of the first gearwheel, the latter is arrested by a catch, and the second gearwheel is positioned more-or-less at a couple location by a machine drive. Thereafter, the pivotable frame member is pivoted, together with the first gearwheel, about the articulating joint in the direction of the stationary frame member, the spring bolt sliding in the centering groove and the rotatable second gearwheel being aligned relative to the arrested first gearwheel so that a given tooth of the first gearwheel is guided into a tooth gap of the second gearwheel, which is provided for the tooth. During the introduction of the given tooth of the first gearwheel into the tooth gap, the first gearwheel must be moved by the pivoting motion somewhat in the radial direction of the second gearwheel so that the so-called insertion direction of the given gearwheel corresponds thereto. The tooth has already passed into the tooth gap, and the gear train is thus closed, before the spring bolt has completely passed through the centering groove and enables a rotary movement of the second gearwheel again.
An unfavorable feature of the device described in the aforementioned German patent document is that, if a second gearwheel is not positioned sufficiently precisely in the coupling position, the spring bolt comes into contact with the segment ring and blocks further movement of the pivotable frame member relative to the stationary frame member, as a result of which the coupling operation is stopped. In this case, a renewed attempt to position the second gearwheel sufficiently precisely in the coupling position is necessary in order for the centering groove to be positioned precisely relative to the spring bolt.
For reasons explained hereinbelow, in so-called xe2x80x9clong printing machinesxe2x80x9d with a large number of printing or varnishing units arranged in a row, such precise positioning of the second gearwheel is not always possible. The gearwheels of the impression cylinder of the printing or varnishing units are connected, via gearwheels of sheet-transporting drums, to form a continuous gear train. A given driving gearwheel of the gear train is connected to an electromotive central drive, which, via the gear train, rotatively drives each of the gearwheels of the gear train.
When the central drive is at a standstill, the driving gearwheel virtually cannot rotate. The greater the number of gearwheels located between the driving gearwheel and a driven gearwheel of the gear train, the more the driven gearwheel can be rotated when the printing machine is at a standstill. This results from each gearwheel pairing being affected by tooth clearance. The greater the number of gearwheel coupling locations provided between the driving gearwheel and the driven gearwheel, the greater the sum of the amounts of coupling-location tooth clearance, it being possible for the driven gearwheel to be rotated by that sum.
A gearwheel which is the farthest remote from the driving gearwheel in the gear train can thus be rotated by the greatest amount. For example, the gearwheel may have assigned thereto an impression cylinder of a varnishing unit arranged at the end of the printing machine and it may correspond to the second gearwheel described in the aforementioned German patent document and to be positioned in the coupling position.
Due to the sum of the amount of tooth clearance of the other gearwheels in the gear train up to the second gearwheel, it is not possible for the second gearwheel to be positioned reliably by the central drive, with the result that it is often the case that the spring bolt comes into contact with the segment ring, and position corrections are thus necessary.
A further disadvantage of the device described in the aforementioned German patent Document is apparent if the second gearwheel, to which the first gearwheel is to be coupled, is the driving gearwheel itself, which is connected to the central drive, or is a gearwheel in the gear train which is located in close proximity to the driving gearwheel. In this case, with the central drive at a standstill, the second gearwheel could only be rotated to a slight extent, if at all, because, between the central drive and the second gearwheel, there is too little total tooth clearance, if any at all, necessary for the rotation of the second gearwheel. In other words, absolutely precise positioning of the second gearwheel in the coupling position would be necessary for the centering groove to be centered precisely relative to the spring bolt. Even if the centering groove is offset slightly relative to the spring bolt, in which case the latter comes into contact with a beveling of the centering groove, coupling of the first gearwheel to the second gearwheel would not be possible because the spring bolt could not force the centering groove, and thus the second gearwheel, out of the rotary position secured by the central drive.
It is thus the case that the device described in the aforementioned German patent document is unsuitable not only for coupling the gearwheels of the varnishing unit which is arranged downline, as viewed in the printing-material transporting direction, of a large number of printing units, is thus remote from the central drive and is used, for example, for the concluding application of a clear protective varnish to a printed image, but also for coupling gearwheels of a varnishing unit which is arranged upline of a large number of printing units, is thus in the vicinity of the central drive and is used, for example, for the application of a zinc white primer to the printing material before the latter is printed in the printing units.
It is accordingly an object of the invention thus to provide a device for ensuring correct engagement of a tooth of a first gearwheel in a second gearwheel, wherein the position of the second gearwheel within a gear train of a printing-material processing machine is not important for disruption-free coupling.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a device for ensuring correct tooth engagement during coupling of an adjustable, first gearwheel to a second gearwheel of a printing-material processing machine, comprising a first adjustment device for adjusting the first gearwheel in a direction towards the second gearwheel during coupling, and further comprising a protrusion and a guide for guiding the protrusion during the coupling, the protrusion being disposed eccentrically to one of the two gearwheels and being connected to the one gearwheel, so that, during rotation of the one gearwheel about a central axis thereof, the protrusion is rotatable together with the one gearwheel.
In accordance with another feature of the invention, the one gearwheel to which the protrusion is connected is the first gearwheel.
In accordance with a further feature of the invention, the first gearwheel is mounted in the first adjustment device for adjusting the central axis of the first gearwheel along a straight line from a first position, wherein the first gearwheel is decoupled from the second gearwheel, into a second position wherein the first gearwheel is coupled to the second gearwheel.
In accordance with an added feature of the invention, the guide is a so-called open guide for guiding the protrusion only on one side.
In accordance with an additional feature of the invention, the gearwheels are provided with a respective helical toothing, and the guide and the protrusion are adapted to the helical toothings.
In accordance with yet another feature of the invention, the protrusion is formed with a supporting surface which is inclined in accordance with an angle of skew of the toothing of the first gearwheel.
In accordance with yet a further feature of the invention, a guide surface of the guide is inclined in accordance with an angle of skew of the toothing of the second gearwheel.
In accordance with yet an added feature of the invention, one of the gearwheels has assigned thereto a second adjustment device for adjusting the one gearwheel relative to the other of the two gearwheels in the axial direction of the one gearwheel.
In accordance with yet an additional feature of the invention, the first gearwheel has assigned thereto the second adjustment device for adjusting the first gearwheel axially parallel to the second gearwheel.
In accordance with still another feature of the invention, connected to the axially adjustable first gearwheel so as to be fixed against rotation relative thereto is a cylinder disposed coaxially with the first gearwheel, and the second adjustment device, together with the gearwheels, forms a device for adjusting a circumferential register of the cylinder.
In accordance with still a further feature of the invention, the guide is connected to the other gearwheel.
In accordance with still an added feature of the invention, one of the two gearwheels is formed of a basic wheel and an auxiliary wheel, the basic wheel and the auxiliary wheel having assigned thereto at least one spring for bracing in a circumferential direction.
In accordance with still an additional feature of the invention, the gearwheel formed of the basic wheel and the auxiliary wheel is the first gearwheel.
In accordance with a concomitant aspect of the invention, there is provided a printing-material processing machine having a device for ensuring correct tooth engagement during coupling of an adjustable, first gearwheel to a second gearwheel of a printing-material processing machine, the ensuring device comprising a first adjustment device for adjusting the first gearwheel in a direction towards the second gearwheel during coupling, and further comprising a protrusion and a guide for guiding the protrusion during the coupling, the protrusion being disposed eccentrically to one of the two gearwheels and being connected to the one gearwheel, so that, during rotation of the one gearwheel about a central axis thereof, the protrusion is rotatable together with the one gearwheel.
The ensuring device according to the invention is distinguished in that the protrusion is arranged eccentrically with respect to one of the two gearwheels (the first gearwheel or the second gearwheel) and is connected to the gearwheel, with the result that, during rotation of the gearwheel about a central axis thereof, the protrusion rotates together with the gearwheel.
One advantage of the ensuring device according to the invention is that, in the device, rotatability of the second gearwheel for the coupling of the first gearwheel is not necessary. It is also the case with the ensuring device according to the invention that there is no need for the first gearwheel to be arrested and, during coupling, the first gearwheel can be aligned in relation to the second gearwheel.
A further advantage of the ensuring device according to the invention can be seen in that the second gearwheel no longer has to be positioned as precisely in the coupling position. Even if the second gearwheel is only positioned roughly in the coupling position, because of the total tooth clearance provided, assurance is always provided that a given tooth of the first gearwheel is guided into a tooth gap of the second gearwheel provided for that given tooth. In the ensuring device according to the invention, there is thus no need for any corrections in the rotary position of the second gearwheel, and proper gearwheel coupling is achieved the very first time in each case.
It is also advantageous that, as the given tooth dips or passes into the tooth gap, the adjustment direction of the first gearwheel may differ from the radial direction of the second gearwheel and the insertion direction of the given tooth. In other words, as the tooth of the first gearwheel dips or passes into the tooth gap of the second gearwheel, the center point of the first gearwheel can be adjusted in a direction other than that extending through the center point of the second gearwheel.
In an embodiment which is advantageous in terms of an angle-of-rotation or rotary-angle alignment of the first gearwheel with the second gearwheel during coupling, the protrusion, which is an element other than the teeth of the first gearwheel, is fastened or integrally formed on the first gearwheel.
In an embodiment which is advantageous in terms of a non-axially parallel adjustment of the first gearwheel in the direction towards the second gearwheel during coupling, and away therefrom during decoupling, by a chain whereon the first gearwheel is suspended, the first adjustment device is constructed for linearly adjusting the first gearwheel from a spaced-apart position into an engagement position relative to the second gearwheel. The first adjustment device, for the vertical adjustment of the first gearwheel from the spaced-apart position into the engagement position and back, is preferably constructed as a chain transmission.
In an embodiment which is advantageous in terms of the protrusion being positioned on the guide transversely to the guidance direction of the guide, the guide is a purely force-coupled, and thus formlocking-free, slide guide. In this regard, it is noted that a formlocking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a forcelocking connection, which locks the elements together by force external to the elements.
In an embodiment which is advantageous in terms of the spur-gear pairing formed from the gearwheels running more smoothly, the gearwheels are provided with helical toothing aligned obliquely relative to the axes of the gearwheels, the protrusion and the guide being constructed so as to correspond to the helical toothing. The latter advantageously allows the first gearwheel to be coupled to the second gearwheel irrespective of different axial positions of the first gearwheel relative to the second gearwheel.
In an embodiment which is advantageous in terms of the protrusion being formed as a counterpart adapted three-dimensionally to the guide, a supporting surface of the protrusion, which abuts the guide, corresponds, in terms of angle of skew and direction of slope, to the toothing of the first gearwheel. In this embodiment, the guide has a surface which corresponds, in terms of angle of skew and direction of slope, to the toothing of the second gearwheel and against which the protrusion abuts and along which, during coupling, the protrusion either slides as a sliding block or rolls as a cam roller, depending upon the form of the protrusion. The angles of skew of the gearwheels are equal to one another, with the result that the angles of skew of the protrusion and of the guide are also equal to one another. The directions of slope of the toothing of the gearwheels are directed counter to one another, and those surfaces of the protrusion and of the guide which come into contact with one another thus also slope in opposite directions. For example, the first gearwheel is provided with toothing which slopes to the left, the tooth-flank lines of which extend in a counterclockwise direction, and the second gearwheel is provided with toothing which slopes to the right, the tooth-flank lines of which extend in a clockwise direction.
In an embodiment which is advantageous in terms of an adjustment of the rotational phase position of one axially displaceably mounted gearwheel (of the first or the second gearwheel) relative to the other gearwheel with the gearwheels in engagement with one another and rotating, one of the two gearwheels has assigned thereto an adjustment device for displacing the gearwheel in the axially parallel direction relative to the other gearwheel, the adjustment device being referred to hereinbelow as the second adjustment device.
In an embodiment which is advantageous in terms of an adjustment of the rotational phase position of the couplable and decouplable, first gearwheel relative to the second gearwheel, the first gearwheel is mounted so that it can be displaced not just perpendicularly to the axial direction of the second gearwheel for coupling purposes, but also in an axial parallel manner relative to the second gearwheel, by the second adjustment device, in the coupled state.
In an embodiment which is advantageous in terms of the adjustment of the position of the print start of a printing or varnishing form on an application cylinder, which is connected to the first gearwheel, relative to the leading edge of the printing-material sheets on an impression cylinder, which is connected to the second gearwheel, the gearwheels, together with the second adjustment device, form a register-adjustment device for the application cylinder.
In an embodiment which is advantageous in terms of the guide being used as an abutment which rotates the protrusion during coupling, the guide is fastened or integrally formed eccentrically on the second gearwheel.
In an embodiment which is advantageous in terms of minimizing the tooth clearance, the second or preferably first gearwheel comprises a basic wheel and an auxiliary wheel which is arranged rotatably and coaxially in relation to the basic wheel and is braced with the basic wheel in the circumferential direction by at least one spring.
The ensuring device according to the invention and the embodiments thereof are suitable particularly for ensuring the correct tooth engagement of two gearwheels of a printing or varnishing unit of a rotary printing machine.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for ensuring correct tooth engagement during coupling of two gearwheels, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.